As known well, an operator of the vehicle such as a passenger car, a truck, a two-wheeled vehicle, a train, a ship, an airplane, etc., is unable to, if the operator's eyes are closed in a way that falls into drowsiness and dozes off or if the axis of sight deviates (from the road) for looking a night scene or manipulating a switch on an instrument panel, an audio system and a cellular phone during the operation, observe a forward situation. If unable to observe the forward situation during the operation, the operator cannot take action of avoiding a danger, and hence there is a high possibility of causing an accident. Therefore, some companies proposed a good number of alarm systems for outputting an alarm from a loudspeaker, a monitor and a light emitting diode lamp when the operator takes an abnormal behavior unsuited to the operation.
In many of those conventional alarm systems, factors (such as closed eye, looking-aside and meandering driving) for judging the abnormal behavior are converted into numerical values, and a hazard state is judged if the factor value exceeds a predetermined threshold value, thereby outputting an alarm. Further, a recent alarm system is that if an abnormal behavior state with the factor value exceeding the predetermined threshold value continues for a fixed period of time, and the alarm is outputted (refer to, e.g., Patent documents 1 through 3).
Patent Document 1
Japanese Patent Application Laid-Open Publication No. 2002-219968 (paragraph 0012)
Patent Document 2
Japanese Patent Application Laid-Open Publication No. 2001-138767 (paragraph 0037)
Patent Document 3
Japanese Patent Application Laid-Open Publication No. 06-032154 (paragraph 0069)
By the way, if the abnormal behavior is conducted for a fixed period of time when the moving speed of the vehicle is 100 km/h, a hazard level largely differs from a case of conducting the abnormal behavior for the same period of time when the moving speed is 10 km/h. An extremely hazardous state occurs when the moving speed is high as in the former case.
Nevertheless, the conventional alarm system described above simply judges the hazard state when the abnormal behavior state continues over the fixed period of time, and therefore judges the hazard state irrespective of the moving speed of the vehicle, i.e., regardless of the level of the danger. Therefore, in the conventional alarm system, the operator of the vehicle was unable to exactly receive the alarm when the danger actually rises.
It is an object of the present invention, which was devised under such circumstances of the prior arts described above, to provide an alarm system capable of exactly outputting the alarm when the danger actually rises, an alarm control apparatus for making this alarm system function in the vehicle, and an alarm control program for making a computer function as this alarm control apparatus.